Wireless IC device and electronic apparatus

ABSTRACT

A wireless IC device that is miniaturized, allows simple and low-cost mounting of a wireless IC, and eliminates the possibility of damage occurring to the wireless IC due to static electricity, and an electronic apparatus equipped with the wireless IC device, includes a wireless IC chip that processes transmission and reception signals, and a feeder circuit substrate that includes a resonant circuit having an inductance element. Feeder electrodes are provided on a surface of the feeder circuit substrate and are electromagnetically coupled to the resonant circuit. The feeder electrodes and are electromagnetically coupled to radiation plates and provided for a printed wiring board. The wireless IC chip is activated by a signal received by the radiation plates and a response signal from the wireless IC chip is radiated outward from the radiation plates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless IC device and, moreparticularly, to a wireless IC device that has a wireless IC used in anRFID (Radio Frequency Identification) system, and an electronicapparatus.

2. Description of the Related Art

In recent years, an RFID system has been developed as an articlemanagement system, which includes a reader/writer that generates aninduction field and an IC chip (also referred to as IC tag or wirelessIC chip) that stores predetermined information allocated to an articleor a casing, and non-contact communication is established between thereader/writer and the IC chip to transmit the information therebetween.

A known existing wireless IC device equipped with an IC chip includes awireless IC tag as described in Japanese Unexamined Patent ApplicationPublication No. 2005-244778. In the wireless IC tag, a dipole antenna(formed of a pair of main antenna elements and matching sections) isprovided on a dielectric substrate, and a tag IC is electricallyconnected to an end portion of the dipole antenna. The matching sectionis arranged between the tag IC and each main antenna element and has thefunction of matching impedance therebetween.

However, the above wireless IC tag has the following problems. First,because each matching section and the corresponding main antenna elementare formed adjacent to each other on a single substrate, the size of thewireless IC tag increases. Second, it is necessary to mount a smallwireless IC chip on an electrode formed on a large substrate on whichthe main antenna elements and the matching sections are arranged, so ahighly accurate mounter is required. In addition, it requires time forpositioning at the time of mounting, so manufacturing time is increased,and cost for the wireless IC tag increases. Third, because the mainantenna elements and the wireless IC chip are connected in anelectrically conductive state, so there is a possibility that thewireless IC chip may be damaged when static electricity enters from themain antenna elements.

In addition, Japanese Unexamined Patent Application Publication No.2000-311226 describes a wireless IC card. The wireless IC card uses anIC chip in which an antenna coil is formed on the surface of the ICchip. In the above wireless IC card, a first antenna coil formed on theIC chip is coupled to a second antenna coil formed on a module substratethrough a magnetic field.

However, in the wireless IC card described in Japanese Unexamined PatentApplication Publication No. 2000-311226, it is necessary to accuratelycontrol the interval between the first and second antenna coils to asize at which a desired coupling is achieved. Specifically, as describedin the paragraph [0107] of Japanese Unexamined Patent ApplicationPublication No. 2000-311226, it is necessary to set the interval to asmaller interval that is smaller than or equal to 20 μm. When the twoantenna coils are coupled with the above small interval, there is aproblem that slight variations in the amount or dielectric constant ofinsulating adhesive arranged between the two antenna coils and inbetween each antenna coil vary a coupled state and, therefore, theradiation characteristic of the wireless IC card decreases. In addition,in order to mount the IC chip on the module substrate at a smallinterval with high accuracy, it requires an expensive mounter, and, as aresult, cost for the wireless IC card increases.

SUMMARY OF THE INVENTION

In view of the above, preferred embodiments of the present inventionprovide a wireless IC device that can achieve miniaturization, allowssimple and low-cost mounting of a wireless IC, and eliminates thepossibility of any damage occurring to the wireless IC due to staticelectricity, and provide an electronic apparatus equipped including sucha novel wireless IC device.

In addition, preferred embodiments of the present invention provide awireless IC device that achieves the advantages of the preferredembodiments described in the preceding paragraph and is able towithstand against an impact due to a drop, or the like, and a stress dueto heat shrinkage, and to provide an electronic apparatus including thenovel IC device.

A wireless IC device according to a preferred embodiment of the presentinvention includes: a wireless IC that processes transmission andreception signals; a feeder circuit substrate including a feeder circuitincorporating an inductance element connected to the wireless IC in agalvanically conductive state and in which a feeder electrode coupled tothe inductance element is provided on a surface of the substrate or aninside of the substrate; and a radiation plate that iselectromagnetically coupled to the feeder electrode.

In the above wireless IC device, the feeder electrode provided on thesurface or inside of the feeder circuit substrate is coupled to theinductance element provided for the feeder circuit substrate and iselectromagnetically coupled to the radiation plate that functions as anantenna. It is not necessary that the feeder circuit substrate isequipped with a radiation plate having a relatively large size. Thus,the feeder circuit substrate may be exceedingly miniaturized. It is onlynecessary that the wireless IC is mounted on the above small feedercircuit substrate. An IC mounter, or the like, used widely in theexisting art may be used, so mounting cost reduces. In addition, whenthe wireless IC is changed in response to the frequency used in an RFIDsystem, it is only necessary to change the design of a resonant circuitand/or matching circuit of the feeder circuit substrate, and it is notnecessary to change the shape or size of the radiation plate. In termsof this point as well, it is possible to achieve low cost.

Particularly, one of the unique features of the wireless IC deviceaccording to the present preferred embodiment is that the feederelectrode is provided for the feeder circuit substrate, and the feederelectrode is coupled to the inductance element and iselectromagnetically coupled to the radiation plate. The inductanceelement is in a galvanically conductive state with the wireless IC; and,when the radiation plate and the feeder electrode are in a galvanicallynon-conductive state, it is possible to prevent any damage occurring tothe wireless IC due to static electricity that enters from the radiationplate.

Note that the wireless IC may be in chip form, and the wireless IC maybe able to rewrite information or may have an information processingfunction other than the RFID system in addition to storing variouspieces of information regarding an article to which the wireless ICdevice is attached.

Another preferred embodiment of the present invention provides anelectronic apparatus that includes the above wireless IC device. Theradiation plate is provided for a printed wiring board incorporated inan apparatus casing, and the feeder electrode provided for the feedercircuit substrate is electromagnetically coupled to the radiation plate.

According to various preferred embodiments of the present invention, itis not necessary that the feeder circuit substrate is equipped with aradiation plate having a relatively large size, so the feeder circuitsubstrate may be exceedingly miniaturized. Therefore, a small wirelessIC may also be easily mounted using an existing mounter. Thus, mountingcost reduces. To change a frequency band used, it is only necessary tochange the design of the resonant circuit. In addition, the feederelectrode provided for the feeder circuit substrate iselectromagnetically coupled to the radiation plate. This eliminates thepossibility that the wireless IC is damaged because of staticelectricity that enters from the radiation plate. In addition, becausethe radiation plate does not sustain any damage due to a bondingmaterial, such as solder, mechanical reliability is greatly improved.

In addition, by providing the mounting electrode on the surface of thefeeder circuit substrate separately from the feeder electrode, thebonding strength of the feeder circuit substrate is greatly improved.Thus, even when the wireless IC device receives an impact because of adrop, or the like, or when thermal stress is applied to the radiationsubstrate or the feeder circuit substrate, it does not adverselyinfluence electromagnetic coupling between the feeder electrode and theradiation plate.

Particularly, the mounting electrode provided on the side surface of thefeeder circuit substrate is fixed to a mounting land different from theradiation plate. Thus, the feeder circuit substrate and the radiationplate are desirably coupled to each other through a simple manufacturingprocess without variations in gap therebetween, and variations in degreeof coupling are substantially eliminated.

Other features, elements, arrangements, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of preferred embodiments of the presentinvention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a wireless IC device according to afirst preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view of a wireless IC device according to asecond preferred embodiment of the present invention.

FIG. 3 is a cross-sectional view of a wireless IC device according to athird preferred embodiment of the present invention.

FIG. 4 is a cross-sectional view of a wireless IC device according to afourth preferred embodiment of the present invention.

FIG. 5 is a cross-sectional view of a wireless IC device according to afifth preferred embodiment of the present invention.

FIG. 6 is a cross-sectional view of a wireless IC device according to asixth preferred embodiment of the present invention.

FIG. 7 is a cross-sectional view of a wireless IC device according to aseventh preferred embodiment of the present invention.

FIG. 8 is a cross-sectional view of a wireless IC device according to aneighth preferred embodiment of the present invention.

FIG. 9 is a cross-sectional view of a wireless IC device according to aninth preferred embodiment of the present invention.

FIG. 10 is a cross-sectional view of a wireless IC device according to atenth preferred embodiment of the present invention.

FIG. 11 is a cross-sectional view of a wireless IC device according toan eleventh preferred embodiment of the present invention.

FIG. 12 is a cross-sectional view of a wireless IC device according to atwelfth preferred embodiment of the present invention.

FIG. 13 is a cross-sectional view of a wireless IC device according to athirteenth preferred embodiment of the present invention.

FIG. 14 is a cross-sectional view of a wireless IC device according to afourteenth preferred embodiment of the present invention.

FIG. 15 is a cross-sectional view of a wireless IC device according to afifteenth preferred embodiment of the present invention.

FIG. 16 is a cross-sectional view of a wireless IC device according to asixteenth preferred embodiment of the present invention.

FIG. 17 is a cross-sectional view of a wireless IC device according to aseventeenth preferred embodiment of the present invention.

FIG. 18 is a plan view of a wireless IC device according to aneighteenth preferred embodiment of the present invention.

FIG. 19 is a perspective view of a wireless IC chip.

FIG. 20 is an exploded perspective view of a feeder circuit substratethat incorporates a first example of a resonant circuit.

FIG. 21 is an equivalent circuit diagram that shows the first example ofthe resonant circuit.

FIG. 22 is an exploded perspective view of a feeder circuit substratethat incorporates a second example of a resonant circuit.

FIG. 23 is an equivalent circuit diagram that shows the second exampleof the resonant circuit.

FIG. 24 is a perspective view of a cellular phone which is a preferredembodiment of an electronic apparatus according to the presentinvention.

FIG. 25 is a view that illustrates a printed wiring board incorporatedin the cellular phone.

FIG. 26 is a cross-sectional view of a wireless IC device mounted on theprinted wiring board.

FIG. 27 is a plan view of the wireless IC device mounted on the printedwiring board.

FIGS. 28A and 28B show a wireless IC device according to a nineteenthpreferred embodiment of the present invention, in which FIG. 28A is across-sectional view and FIG. 28B is a plan view of a radiation plate.

FIG. 29 is a plan view of a radiation plate of a wireless IC deviceaccording to a twentieth preferred embodiment of the present invention.

FIG. 30 is a plan view of a radiation plate of a wireless IC deviceaccording to a twenty-first preferred embodiment of the presentinvention.

FIG. 31 is a plan view of a radiation plate of a wireless IC deviceaccording to a twenty-second preferred embodiment of the presentinvention.

FIGS. 32A and 32B show a wireless IC device according to a twenty-thirdpreferred embodiment of the present invention, in which FIG. 32A is across-sectional view of a wireless IC chip and a feeder circuitsubstrate and FIG. 32B is a plan view of a radiation plate.

FIG. 33 is a cross-sectional view of a wireless IC device according to atwenty-fourth preferred embodiment of the present invention.

FIG. 34 is a cross-sectional view of a wireless IC device according to atwenty-fifth preferred embodiment of the present invention.

FIG. 35 is a plan view of a radiation plate of a wireless IC deviceaccording to a twenty-sixth preferred embodiment of the presentinvention.

FIG. 36 is a plan view of a radiation plate of a wireless IC deviceaccording to a twenty-seventh preferred embodiment of the presentinvention.

FIGS. 37A and 37B show a wireless IC device according to a twenty-eighthpreferred embodiment of the present invention, in which FIG. 37A is across-sectional view and FIG. 37B is a plan view of a radiation plate.

FIGS. 38A and 38B shows a wireless IC device according to a twenty-ninthpreferred embodiment of the present invention, in which FIG. 38A is across-sectional view and FIG. 38B is a plan view of a radiation plate.

FIGS. 39A and 39B show a wireless IC device according to a thirtiethpreferred embodiment of the present invention, in which FIG. 39A is across-sectional view and FIG. 39B is a plan view of a radiation plate.

FIG. 40 is a perspective view of a wireless IC device according to athirty-first preferred embodiment of the present invention.

FIG. 41 is a cross-sectional view related to a relevant portion of thewireless IC device according to the thirty-first preferred embodiment ofthe present invention.

FIG. 42 is a perspective view of a wireless IC device according to athirty-second preferred embodiment of the present invention.

FIG. 43 is a cross-sectional view related to a relevant portion of thewireless IC device according to the thirty-second preferred embodimentof the present invention.

FIG. 44 is a perspective view of an alternative example of a feedercircuit substrate.

FIG. 45 is an equivalent circuit diagram of a feeder circuit thatconstitutes a first example of the feeder circuit substrate.

FIG. 46 is a plan view that shows the laminated structure of the firstexample of the feeder circuit substrate.

FIG. 47 is an equivalent circuit diagram of a feeder circuit thatconstitutes a second example of the feeder circuit substrate.

FIG. 48 is a perspective view that shows the laminated structure of thesecond example of the feeder circuit substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of a wireless IC device and anelectronic apparatus according to the present invention will bedescribed with reference to the accompanying drawings. Note that in thedrawings, like reference numerals denote like components or portions,and the overlap description is omitted.

First Preferred Embodiment of Wireless IC Device, See FIG. 1

FIG. 1 shows a wireless IC device according to a first preferredembodiment of the present invention. The wireless IC device 1 includes awireless IC chip 5, a feeder circuit substrate 10, and radiation plates21 a and 21 b. The wireless IC chip 5 processes transmission andreception signals of a predetermined frequency. The wireless IC chip 5is mounted on the feeder circuit substrate 10. The radiation plates 21 aand 21 b are provided for a radiation substrate (printed wiring board)20.

The wireless IC chip 5 preferably includes a clock circuit, a logiccircuit, a memory circuit, and the like. The wireless IC chip 5 storesnecessary information. As shown in FIG. 19, input/output terminalelectrodes 6 and mounting terminal electrodes 7 are provided on the backsurface of the wireless IC chip 5. The input/output terminal electrodes6 are electrically connected to electrodes 12 a and 12 b (see FIG. 20)via metal bumps 8. The electrodes 12 a and 12 b are provided on thesurface of the feeder circuit substrate 10. In addition, the mountingterminal electrodes 7 are electrically connected to electrodes 12 c and12 d via metal bumps 8. Note that the material of each metal bump 8 maybe Au, Ag, solder, or other suitable material.

In addition, a protection film 9 is arranged on the surface of thefeeder circuit substrate 10 so as to cover a portion connecting with thewireless IC chip 5 in order to improve the bonding strength between thewireless IC chip 5 and the feeder circuit substrate 10.

The radiation plates 21 a and 21 b are arranged so that an electrodefilm formed of a conductive paste or metal plating such as Al, Cu and Agis provided in a predetermined shape in the radiation substrate 20having a multilayer structure. Electrodes 26 a and 26 b are provided onthe surface of the radiation substrate 20. Note that the radiationsubstrate 20 is not limited to a printed wiring board made of glassepoxy resin but it may be formed of a resin substrate, made of anotherresin, or a ceramic substrate.

The feeder circuit substrate 10 incorporates a resonant circuit (notshown in FIG. 1) having an inductance element. Feeder electrodes 19 aand 19 b are provided on the back surface of the feeder circuitsubstrate 10. The connecting electrodes 12 a to 12 d (see FIG. 20) aredisposed on the surface of the feeder circuit substrate 10. The feederelectrodes 19 a and 19 b are coupled to the resonant circuitincorporated in the substrate 10. In addition, the feeder electrodes 19a and 19 b are connected to the electrodes 26 a and 26 b via conductiveadhesive 22 in an electrically conductive state. The electrodes 26 a and26 b are provided on the radiation substrate 20. That is, the feederelectrodes 19 a and 19 b are capacitively coupled to the radiationplates 21 a and 21 b via the electrodes 26 a and 26 b and the conductiveadhesive 22 in an electrically non-conductive state. Note thatinsulating adhesive or solder may be used instead of the conductiveadhesive 22. In addition, the electrodes 26 a and 26 b are notnecessary.

The feeder circuit substrate 10 incorporates the resonant circuit havinga predetermined resonant frequency. The feeder circuit substrate 10transmits a transmission signal having a predetermined frequency, outputfrom the wireless IC chip 5, to the radiation plates 21 a and 21 b viathe feeder electrodes 19 a and 19 b, or the like, and selects areception signal having a predetermined frequency among signals receivedby the radiation plates 21 a and 21 b and then supplies the receptionsignal to the wireless IC chip 5. Therefore, in the wireless IC device1, the wireless IC chip 5 is activated by a signal received by theradiation plates 21 a and 21 b, and a response signal from the wirelessIC chip 5 is radiated outward from the radiation plates 21 a and 21 b.

In the wireless IC device 1, the feeder electrodes 19 a and 19 bprovided on the surface of the feeder circuit substrate 10 are coupledto the resonant circuit incorporated in the substrate 10, and arecoupled to the radiation plates 21 a and 21 b, which function as anantenna, in an electrically non-conductive state. It is not necessarythat the feeder circuit substrate 10 is equipped with the radiationplates 21 a and 21 b having a relatively large size. Thus, the feedercircuit substrate 10 may be exceedingly miniaturized. The wireless ICchip 5 may be mounted on the above small feeder circuit substrate 10. Amounter, or the like, used widely in the existing art may be used, somounting cost is greatly reduced. In addition, to change a frequencyband used, it is only necessary to change the design of the resonantcircuit, and the radiation plates 21 a and 21 b, and the like, may beused without any change. In addition, the radiation plates 21 a and 21 bare in an electrically non-conductive state with the feeder electrodes19 a and 19 b. Thus, static electricity that enters from the radiationplates 21 a and 21 b is not applied to the wireless IC chip 5. Thisprevents any damage occurring to the wireless IC chip 5 due to staticelectricity.

Second Preferred Embodiment of Wireless IC Device, See FIG. 2

FIG. 2 shows a wireless IC device according to a second preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that the feeder electrodes 19a and 19 b are arranged over a range from the back surface of the feedercircuit substrate 10 to both side surfaces thereof. The feederelectrodes 19 a and 19 b are further strongly coupled to the radiationplates 21 a and 21 b. The other operations and advantages are similar tothose of the first preferred embodiment.

Third Preferred Embodiment of Wireless IC Device, See FIG. 3

FIG. 3 shows a wireless IC device according to a third preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment. Aprotection film 23 made of epoxy-based resin or polyimide-based resin isarranged on the surface of the feeder circuit substrate 10 to cover thewireless IC chip 5. By providing the protection film 23, theenvironmental resistance improves. The other operations and advantagesare similar to those of the first preferred embodiment.

Fourth Preferred Embodiment of Wireless IC Device, See FIG. 4

FIG. 4 shows a wireless IC device according to a fourth preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that the electrodes 26 a and26 b are extended to both sides to also function as radiation plates.The other operations and advantages are similar to those of the firstpreferred embodiment.

Fifth Preferred Embodiment of Wireless IC Device, See FIG. 5

FIG. 5 shows a wireless IC device according to a fifth preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that the multilayer radiationsubstrate 20 includes two layers of the radiation plates 21 a and 21 band the electrodes 26 c and 26 d, respectively. The electrodes 26 a and26 b are provided on the surface of the radiation substrate 20 and thenthe electrodes 26 a and 26 b and the electrodes 26 c and 26 d arerespectively electrically connected through via hole conductors 27.

In the fifth preferred embodiment, the radiation plates 21 a and 21 bare mainly capacitively coupled to the electrodes 26 c and 26 d, and theelectrodes 26 a and 26 b are respectively connected to the electrodes 26c and 26 d through the via hole conductors 27 and are electricallyconnected to the feeder electrodes 19 a and 19 b through the conductiveadhesive 22. Thus, the operations and advantages of the fifth preferredembodiment are similar to those of the first preferred embodiment.

Sixth Preferred Embodiment of Wireless IC Device, See FIG. 6

FIG. 6 shows a wireless IC device according to a sixth preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that the multilayer radiationsubstrate 20 includes the three-layer radiation plates 21 a and 21 b.The respective radiation plates 21 a and 21 b are mainly capacitivelycoupled to the feeder electrodes 19 a and 19 b, provided on the feedercircuit substrate 10, via the electrodes 26 a and 26 b, and the like, sothe radiation characteristic is greatly improved. In addition, becausethe radiation plates having different lengths are provided, it ispossible to widen the frequency band used in the wireless IC device. Theother operations and advantages are similar to those of the firstpreferred embodiment.

Seventh Preferred Embodiment of Wireless IC Device, See FIG. 7

FIG. 7 shows a wireless IC device according to a seventh preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that the radiation plates 21a and 21 b are provided in the multilayer radiation substrate 20 to havea coil shape through via hole conductors 28. Respective one ends of thecoil-shaped radiation plates 21 a and 21 b are mainly capacitivelycoupled to the feeder electrodes 19 a and 19 b, provided on the feedercircuit substrate 20, through the electrodes 26 a and 26 b, and thelike. By forming the radiation plates 21 a and 21 b in a coil shape, theradiation characteristic is greatly improved. The other operations andadvantages are similar to those of the first preferred embodiment.

Eighth Preferred Embodiment of Wireless IC Device, See FIG. 8

FIG. 8 shows a wireless IC device according to an eighth preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that a resonant circuitincludes an element incorporated in the feeder circuit substrate 10 andan element 71 mounted on the feeder circuit substrate 10. The element 71is a chip inductor, a chip capacitor, or other suitable electroniccomponent. The chip-type element may have a large inductance or a largecapacitance, and the element incorporated in the feeder circuitsubstrate 10 may have a small inductance or a small capacitance. Thus,it is possible to further miniaturize the feeder circuit substrate 10.The other operations and advantages are similar to those of the firstpreferred embodiment.

Ninth Preferred Embodiment of Wireless IC Device, See FIG. 9

FIG. 9 shows a wireless IC device according to a ninth preferredembodiment of the present invention. The wireless IC device 1 basicallyhas a similar configuration to that of the first preferred embodiment.The wireless IC device 1 is constructed so that a resonant circuitincludes an element incorporated in the feeder circuit substrate 10 andthe element 71 mounted on the radiation substrate 20. The element 71 maybe a chip inductor, a chip capacitor, or other suitable electroniccomponent, as described in the eight preferred embodiment, and theoperations and advantages are similar to those of the eighth preferredembodiment.

Tenth Preferred Embodiment of Wireless IC Device, See FIG. 10

FIG. 10 shows a wireless IC device according to a tenth preferredembodiment of the present invention. The wireless IC device 1 isconstructed so that various electronic circuit components other than thewireless IC device 1 are mounted on a printed wiring board 20 whichserves as a radiation substrate. In other words, the wireless IC device1 is mounted on the printed wiring board 20 incorporated in a wirelesscommunication device, such as a cellular phone, and the wireless ICdevice 1 has a similar configuration to that of the first preferredembodiment. In addition, the radiation plates 21 a and 21 b may have thefunction of a ground electrode or a shield electrode.

In the tenth preferred embodiment, the mounted electronic circuitcomponents, for example, include a chip resistor 72 and a wirelesscommunication circuit 73 on which IC components are mounted. Note thatin the first to tenth preferred embodiments, the radiation plates 21 aand 21 b may be disposed on the back surface of the radiation substrate20.

Eleventh Preferred Embodiment of Wireless IC Device, See FIG. 11

FIG. 11 shows a wireless IC device according to an eleventh preferredembodiment of the present invention. The wireless IC device 1, as wellas the tenth preferred embodiment, is mounted on the printed wiringboard 20 incorporated in a wireless communication device. In addition tothe chip resistor 72 and the wireless communication circuit 73, awireless communication circuit 74, a chip capacitor 75 and a circuitsubstrate 76 are mounted on a surface opposite to a principal surface onwhich the feeder circuit substrate 10 is mounted. At this time, theradiation plates 21 a and 21 b may have the function of a groundelectrode or a shield electrode.

Twelfth Preferred Embodiment of Wireless IC Device, See FIG. 12

FIG. 12 shows a wireless IC device according to a twelfth preferredembodiment of the present invention. The wireless IC device 1, as wellas the eleventh preferred embodiment, is mounted on the printed wiringboard 20 incorporated in a wireless communication device. A shieldelectrode 77 is incorporated in the printed wiring board 20 in order toprovide magnetic shield between components on the surface and componentson the back surface.

Thirteenth Preferred Embodiment of Wireless IC Device, See FIG. 13

FIG. 13 shows a wireless IC device according to a thirteenth preferredembodiment of the present invention. The wireless IC device 1, as wellas the tenth preferred embodiment, is mounted on the printed wiringboard 20 incorporated in a wireless communication device. The shieldelectrode 77 is incorporated in the substrate 20 in order to providemagnetic shield between the feeder circuit substrate 10 and the wirelessIC chip 5, which are provided on the surface, and the wirelesscommunication circuit 74, the chip resistor 75 and the circuit substrate76, which are provided on the back surface.

Fourteenth Preferred Embodiment of Wireless IC Device, See FIG. 14

FIG. 14 shows a wireless IC device according to a fourteenth preferredembodiment of the present invention. The wireless IC device 1, as wellas the tenth to thirteenth preferred embodiments, is mounted on theprinted wiring board 20 incorporated in a wireless communication device.The radiation plates 21 a and 21 b each are laminated between the shieldelectrodes 77. The radiation plates 21 a and 21 b are mainlycapacitively coupled to the feeder electrodes 19 a and 19 b, provided onthe feeder circuit substrate 10, through the electrodes 26 a and 26 b,and the like.

Fifteenth Preferred Embodiment of Wireless IC Device, See FIG. 15

FIG. 15 shows a wireless IC device according to a fifteenth preferredembodiment of the present invention. The wireless IC device 1 is mountedon the printed wiring board 20 incorporated in a wireless communicationdevice. The feeder circuit substrate 10 equipped with the wireless ICchip 5 is mounted on a side surface of the printed wiring board 20. Thefeeder electrode 19 is electromagnetically coupled to the radiationplate 21 provided in the substrate 20 in an electrically non-conductivestate. In addition, electronic components 78, such as chip resistors,are mounted on both front and back surfaces of the printed wiring board20, and the plurality of shield electrodes 77 are provided inside theprinted wiring board 20.

Sixteenth Preferred Embodiment of Wireless IC Device, See FIG. 16

FIG. 16 shows a wireless IC device according to a sixteenth preferredembodiment of the present invention. The wireless IC device 1 is mountedon the printed wiring board 20 incorporated in a wireless communicationdevice. The feeder circuit substrate 10 equipped with the wireless ICchip 5 is mounted on a side surface of the printed wiring board 20. Thefeeder electrode 19 is provided on a side surface of the feeder circuitsubstrate 10, and the feeder electrode 19 is electromagnetically coupledto the radiation plate 21 provided inside the substrate 20 in anelectrically non-conductive state. In addition, the electroniccomponents 78, such as chip resistors, are mounted on both front andback surfaces of the printed wiring board 20, and the plurality ofshield electrodes 77 are provided inside the printed wiring board 20.

Seventeenth Preferred Embodiment of Wireless IC Device, See FIG. 17

FIG. 17 shows a wireless IC device according to a seventeenth preferredembodiment of the present invention. The wireless IC device 1 isaccommodated inside the printed wiring board 20 incorporated in awireless communication device, and the feeder electrode 19 iselectromagnetically coupled to the radiation plate 21 provided insidethe substrate 20 in an electrically non-conductive state. In addition,the electronic components 78, such as chip resistors, are mounted onboth front and back surfaces of the printed wiring board 20, and theplurality of shield electrodes 77 are provided inside the printed wiringboard 20.

Eighteenth Preferred Embodiment of Wireless IC Device, See FIG. 18

FIG. 18 shows a wireless IC device according to an eighteenth preferredembodiment of the present invention. FIG. 18 is a plan view. Thewireless IC device 1 is accommodated in a recess 20 a formed on a sidesurface of the printed wiring board 20. The feeder electrode 19 providedon the back surface of the feeder circuit substrate 10 iselectromagnetically coupled to the radiation plate 21 provided insidethe substrate 20 in an electrically non-conductive state.

First Example of Resonant Circuit, See FIG. 20 and FIG. 21

A first example of a resonant circuit incorporated in the feeder circuitsubstrate 10 is shown as an exploded perspective view of the feedercircuit substrate 10 in FIG. 20, and is also shown as an equivalentcircuit in FIG. 21.

As shown in FIG. 20, the feeder circuit substrate 10 is constructed sothat laminated ceramic sheets 11A to 11H made of dielectric material arepressure-bonded and fired. The connecting electrodes 12 a and 12 b,electrodes 12 c and 12 d and via hole conductors 13 a and 13 b areformed in the sheet 11A. A capacitor electrode 18 a, conductor patterns15 a and 15 b and via hole conductors 13 c to 13 e are formed in thesheet 11B. A capacitor electrode 18 b and via hole conductors 13 d to 13f are formed in the sheet 11C. Furthermore, conductor patterns 16 a and16 b and via hole conductors 13 e, 13 f, 14 a, 14 b and 14 d are formedin the sheet 11D. Conductor patterns 16 a and 16 b and via holeconductors 13 e, 13 f, 14 a, 14 c and 14 e are formed in the sheet 11E.A capacitor electrode 17, conductor patterns 16 a and 16 b and via holeconductors 13 e, 13 f, 14 f and 14 g are formed in the sheet 11F.Conductor patterns 16 a and 16 b and via hole conductors 13 e, 13 f, 14f and 14 g are formed in the sheet 11G. Conductor patterns 16 a and 16 band a via hole conductor 13 f are formed in the sheet 11H.

By laminating the sheets 11A to 11H, an inductance element L1 is definedby the conductor patterns 16 a that are spirally connected through thevia hole conductors 14 c, 14 d and 14 g, an inductance element L2 isdefined by the conductor patterns 16 b that are spirally connectedthrough the via hole conductors 14 b, 14 e and 14 f, a capacitanceelement C1 is defined by the capacitor electrodes 18 a and 18 b, and acapacitance element C2 is defined by the capacitor electrodes 18 b and17.

One end of the inductance element L1 is connected to the capacitorelectrode 18 b through the via hole conductors 14 c and 13 d, theconductor pattern 15 a and the via hole conductor 13 c. One end of theinductance element L2 is connected to the capacitor electrode 17 throughthe via hole conductor 14 a. In addition, the other ends of theinductance elements L1 and L2 are integrated in the sheet 11H, andconnected to the connecting electrode 12 a through the via holeconductor 13 e, the conductor pattern 15 b and the via hole conductor 13a. Furthermore, the capacitor electrode 18 a is electrically connectedto the connecting electrode 12 b through the via hole conductor 13 b.

Then, the connecting electrodes 12 a and 12 b are electrically connectedto the terminal electrodes 6 (see FIG. 19) of the wireless IC chip 5through the metal bumps 8 (see FIG. 1, or the like). The electrodes 12 cand 12 d are connected to the terminal electrodes 7 of the wireless ICchip 5.

In addition, the feeder electrodes 19 a and 19 b are provided on theback surface of the feeder circuit substrate 10, for example, byapplying conductive paste. The feeder electrode 19 a iselectromagnetically coupled to the inductance elements L (L1 and L2).The feeder electrode 19 b is electrically connected to the capacitorelectrode 18 b through the via hole conductor 13 f. The feederelectrodes 19 a and 19 b are coupled to the radiation plates 21 a and 21b in an electrically non-conductive state, as described above. Theequivalent circuit of the above described resonant circuit is shown inFIG. 21.

Note that in the resonant circuit, the inductance elements L1 and L2 arestructured so that the two conductor patterns 16 a and 16 b are arrangedin parallel or substantially parallel with each other. The two conductorpatterns 16 a and 16 b have different line lengths, so differentresonant frequencies may be set for the two conductor patterns 16 a and16 b. Thus, the wireless IC device 1 may have a wide band.

Note that the ceramic sheets 11A to 11H may be made of a magneticceramic material, and the feeder circuit substrate 10 may be easilyobtained by a process of manufacturing a multilayer substrate, such assheet lamination and thick film printing, used in the existing art.

In addition, it is also possible that the sheets 11A to 11H are formedas a flexible sheet made of a dielectric material, such as polyimide andliquid crystal polymer, electrodes and conductors are formed on thesheets by thick film forming, or the like, those sheets are laminatedand thermally bonded to form a laminated body, and the inductanceelements L1 and L2 and the capacitance elements C1 and C2 areincorporated in the laminated body.

In the feeder circuit substrate 10, the inductance elements L1 and L2and the capacitance elements C1 and C2 are provided at differentpositions in plan view. The feeder circuit substrate 10 iselectromagnetically coupled to the feeder electrode 19 a (radiationplate 21 a) by the inductance elements L1 and L2. The feeder circuitsubstrate 10 is capacitively coupled to the radiation plate 21 b by thecapacitance element C1.

Thus, the wireless IC device 1, in which the wireless IC chip 5 ismounted on the feeder circuit substrate 10, receives a high-frequencysignal (for example, UHF frequency band) radiated from a reader/writer(not shown) by the radiation plates 21 a and 21 b, resonates theresonant circuit that is magnetically and electrically coupled to thefeeder electrodes 19 a and 19 b, and supplies only a reception signal ofa predetermined frequency band to the wireless IC chip 5. On the otherhand, the wireless IC device 1 extracts predetermined energy from thereception signal, and matches information stored in the wireless IC chip5 with a predetermined frequency in the resonant circuit using thepredetermined energy as a driving source. After that, the wireless ICdevice 1 transmits the information to the radiation plates 21 a and 21 bthrough the feeder electrodes 19 a and 19 b, and then transmits andtransfers the information from the radiation plates 21 a and 21 b to thereader/writer.

In the feeder circuit substrate 10, a resonant frequency characteristicis determined by the resonant circuit formed of the inductance elementsL1 and L2 and the capacitance elements C1 and C2. The resonant frequencyof a signal radiated from the radiation plates 21 a and 21 b issubstantially determined by the self resonance frequency of the resonantcircuit. Note that the circuit in the feeder circuit substrate 10 ispreferably designed so that the imaginary portion of an input/outputimpedance of the wireless IC chip 5 conjugates with the imaginaryportion of an impedance when viewed from the connecting electrodes 12 aand 12 b on the feeder circuit substrate 10 toward the feeder electrodes19 a and 19 b, thus making it possible to efficiently transmit andreceive signals.

Incidentally, the resonant circuit also serves as a matching circuit formatching the impedance of the wireless IC chip 5 with the impedance ofthe radiation plates 21 a and 21 b. The feeder circuit substrate 10 mayinclude a matching circuit that is provided separately from the resonantcircuit including the inductance element and the capacitance element (inthis sense, the resonant circuit is also referred to as a matchingcircuit). If the function of a matching circuit is added to the resonantcircuit, the design of the resonant circuit tends to be complex. When amatching circuit is provided separately from the resonant circuit, it ispossible to design the resonant circuit and the matching circuitseparately.

In addition, the feeder circuit substrate 10 may include only a matchingcircuit. Furthermore, the circuit in the feeder circuit substrate 10 mayinclude only an inductance element. In this case, the inductance elementhas the function of matching the impedance between the radiation plates21 a and 21 b and the wireless IC chip 5.

In addition, as described in the eighth and ninth preferred embodiments,some of the elements that constitute the resonant circuit may be mountedon the substrate 10 or the substrate 20.

Second Example of Resonant Circuit, See FIG. 22 and FIG. 23

A second example of a resonant circuit incorporated in a feeder circuitsubstrate 30 is shown as an exploded perspective view of the feedercircuit substrate 30 in FIG. 22, and is also shown as an equivalentcircuit in FIG. 23.

As shown in FIG. 22, the feeder circuit substrate 30 is constructed sothat laminated ceramic sheets 31A to 31E made of a dielectric materialare pressure-bonded and fired. The connecting electrodes 12 a and 12 b,electrodes 12 c and 12 d and via hole conductors 33 a and 33 b aredisposed in the sheet 31A. Conductor patterns 36 and via hole conductors33 c and 33 d are disposed in the sheets 31B, 31C and 31D. A conductorpattern 36 and a via hole conductor 33 e are disposed in the sheet 33E.

By laminating the above sheets 31A to 31E, an inductance element Lincludes the conductor patterns 36 that are spirally connected by thevia hole conductors 33 c. In addition, a capacitance element C isdefined by the line capacity of the conductor patterns 36. One end ofthe inductance element L is connected to the connecting electrode 12 athrough the via hole conductor 33 a.

In addition, the feeder electrode 19 is provided on the back surface ofthe feeder circuit substrate 30 by, for example, applying conductivepaste. The feeder electrode 19 is connected to the other end of theinductance element L through the via hole conductor 33 e, and isconnected to the connecting electrode 12 b through the via holeconductors 33 d and 33 b. The feeder electrode 19 is coupled to theradiation plate 21 in an electrically non-conductive state. Theequivalent circuit of the above described resonant circuit is shown inFIG. 23.

The resonant circuit is constructed so that the wireless IC chip 5 isgalvanically connected to the feeder electrode 19, and supplies ahigh-frequency signal received by the radiation plate 21 to the wirelessIC chip 5. On the other hand, information stored in the wireless IC chip5 is transmitted to the feeder electrode 19 and the radiation platethrough the resonant circuit to transmit and transfer the informationfrom the radiation plate 21 to a reader/writer.

Preferred Embodiment of Electronic Apparatus, See FIG. 24 to FIG. 27

Next, a cellular phone, which is one preferred embodiment of anelectronic apparatus according to the present invention, will bedescribed. A cellular phone 50 shown in FIG. 24 is able to handle aplurality of frequencies, and a terrestrial digital signal, a GPSsignal, a WiFi signal, a communication signal, such as CDMA and GSM, areinput to the cellular phone 50.

As shown in FIG. 25, a printed wiring board 55 is installed in a casing51. A wireless communication circuit 60 and the wireless IC device 1 arearranged on the printed wiring board 55. The wireless communicationcircuit 60 preferably includes an IC 61, a balun 62, incorporated in theboard 55, a BPF 63 and a capacitor 64. The feeder circuit substrate 10,equipped with the wireless IC chip 5, is mounted so that the feederelectrodes 19 a and 19 b are coupled to the radiation plates 21 a and 21b, provided for the printed wiring board 55, in an electricallynon-conductive state, thus forming the wireless IC device 1.

The wireless IC device 1 mounted on the printed wiring board 55 may bethe one shown in FIG. 26 and FIG. 27. The wireless IC device 1 isconstructed so that the feeder electrodes 19 a and 19 b are provided onboth side portions of the feeder circuit substrate 10 on which thewireless IC chip 5 is mounted, and the feeder electrodes 19 a and 19 bare coupled to the radiation plates 21 a and 21 b provided for the board55 in an electrically non-conductive state. The resonant circuit in thefeeder circuit substrate 10 is, for example, the one shown in FIG. 20.

A ground pattern 56 indicated by oblique lines in FIG. 27 is provided onthe surface of the printed wiring board 55, and the wireless IC device 1is mounted in an area 56 a in which the ground pattern 56 is notlocated. In addition, the radiation plates 21 a and 21 b are preferablyarranged in a meander shape. Note that the ground pattern 56 ispreferably spaced apart from the radiation plates 21 a and 21 b to anextent such that the ground pattern 56 does not influence the radiationcharacteristic of the radiation plates 21 a and 21 b.

Nineteenth Preferred Embodiment of Wireless IC Device, See FIGS. 28A and28B

FIGS. 28A and 28B shows a wireless IC device according to a nineteenthpreferred embodiment of the present invention. The nineteenth preferredembodiment to a thirtieth preferred embodiment described below areconstructed so that mounting electrodes 18 a to 18 d are provided forthe feeder circuit substrate 10 in addition to the feeder electrodes 19,19 a and 19 b described in the first preferred embodiment to theeighteenth preferred embodiment.

Specifically, in the nineteenth preferred embodiment, the feederelectrodes 19 a and 19 b are incorporated in the feeder circuitsubstrate 10, and are electromagnetically coupled to coupling portions21 a′ and 21 b′, which are one end portions of the radiation plates 21 aand 21 b arranged to have a meander shape, in an electricallynon-conductive state. The mounting electrodes 18 a and 18 b are disposedon the back surface of the feeder circuit substrate 10, and mountedelectrodes 24 a and 24 b are disposed on the radiation substrate 20. Themounting electrodes 18 a and 18 b and the mounted electrodes 24 a and 24b are respectively connected by a conductive material (which may beelectrically insulating adhesive) such as solder 41.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Inaddition, in the nineteenth preferred embodiment, the mountingelectrodes 18 a and 18 b are provided on the back surface of the feedercircuit substrate 10 and are connected to the mounted electrodes 24 aand 24 b provided on the radiation substrate 20. Thus, the bondingstrength between the feeder circuit substrate 10 and the radiationsubstrate 20 improves. In addition, even when the wireless IC devicereceives an impact due to a drop, or the like, or even when theradiation substrate 20 or the feeder circuit substrate 10 thermallycontracts to generate thermal stress, electromagnetic coupling betweenthe feeder electrodes 19 a and 19 b and the radiation plates 21 a and 21b is not adversely influenced.

Twentieth Preferred Embodiment of Wireless IC Device, See FIG. 29

FIG. 29 shows a wireless IC device according to a twentieth preferredembodiment of the present invention. The twentieth preferred embodimentbasically has a similar configuration to those of the first tonineteenth preferred embodiments, and differs from the first tonineteenth preferred embodiments in that a single mounted electrode 24is provided on the radiation substrate 20 so that the mounted electrode24 is placed between the coupling portions 21 a′ and 21 b′, which areone ends of the radiation plates 21 a and 21 b. A single mountingelectrode (not shown) is provided on the back surface of the feedercircuit substrate 10 at a position facing the mounted electrode 24, andis connected to the mounted electrode 24 through solder or adhesive.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrode aresimilar to those of the nineteenth preferred embodiment. In addition,the mounting electrode is preferably located in the middle portion, soit is possible to extend the radiation plates 21 a and 21 b from a sidein the longitudinal direction of the feeder circuit substrate 10. Inaddition, stress applied to a protruding portion reduces againstwarpage, or the like, of the feeder circuit substrate 10.

Twenty-First Preferred Embodiment of Wireless IC Device, See FIG. 30

FIG. 30 shows a wireless IC device according to a twenty-first preferredembodiment of the present invention. The twenty-first preferredembodiment basically has a similar configuration to those of the firstto twentieth preferred embodiments, and differs from the first totwentieth preferred embodiments in that two mounted electrodes 24 a and24 b are provided on the radiation substrate 20 so that the mountedelectrodes 24 a and 24 b are placed between the coupling portions 21 a′and 21 b′, which are one ends of the radiation plates 21 a and 21 b. Themounted electrodes 24 a and 24 b are arranged in the long sidedirection. Instead, the mounted electrodes 24 a and 24 b may be arrangedin the short side direction or may be arranged in a diagonal linedirection. The mounting electrodes (not shown) are provided on the backsurface of the feeder circuit substrate 10 at positions facing themounted electrodes 24 a and 24 b, and are connected to the mountedelectrodes 24 a and 24 b through solder or adhesive, for example.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrodes arethose described in the nineteenth preferred embodiment.

Twenty-Second Preferred Embodiment of Wireless IC Device, See FIG. 31

FIG. 31 shows a wireless IC device according to a twenty-secondpreferred embodiment of the present invention. The twenty-secondpreferred embodiment basically has a similar configuration to those ofthe first to nineteenth preferred embodiments, and differs from thefirst to nineteenth preferred embodiments in that four mounted electrode24 a to 24 d are provided on the radiation substrate 20 at outer edgesof the feeder circuit substrate 10. The coupling portions 21 a′ and 21b′, which are one ends of the radiation plates 21 a and 21 b, arearranged at the center portion through a gap between the mountedelectrodes 24 a and 24 b and a gap between the mounted electrodes 24 cand 24 d. The mounting electrodes (not shown) are provided on the backsurface of the feeder circuit substrate 10 at positions facing themounted electrodes 24 a to 24 d, and are connected to the mountedelectrodes 24 a to 24 d through solder or adhesive, for example.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrodes arethose described in the nineteenth preferred embodiment. Particularly, inthe twenty-second preferred embodiment, the mounting electrodes and themounted electrodes 24 a to 24 d are provided at the outer edge portionsof the feeder circuit substrate 10. This improves the accuracy of aposition when the feeder circuit substrate 10 is mounted on theradiation substrate 20 using reflow solder. That is, this is because,during reflow soldering, self-alignment effect due to the surfacetension of solder arises at each of the four electrodes 24 a to 24 dlocated at the outer edge portions.

Twenty-Third Preferred Embodiment of Wireless IC Device, See FIGS. 32Aand 32B

FIGS. 32A and 32B show a wireless IC device according to a twenty-thirdpreferred embodiment of the present invention. The twenty-thirdpreferred embodiment basically has a similar configuration to those ofthe first to nineteenth preferred embodiments, and differs from thefirst to nineteenth preferred embodiments in that the mountingelectrodes 18 a to 18 d are formed on both side surfaces (on the nearside and far side with respect to the sheet of FIGS. 32A and 32B) of thefeeder circuit substrate 10. The mounted electrodes 24 a to 24 d areformed on the radiation substrate 20 at positions corresponding to themounting electrodes 18 a to 18 d so that the mounted electrodes 24 a to24 d protrude outward from the outline of the feeder circuit substrate10, and are connected to the mounting electrodes 18 a to 18 d throughsolder or adhesive.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrodes 18a to 18 d are those described in the nineteenth preferred embodiment.Particularly, in the twenty-third preferred embodiment, the mountingelectrodes 18 a to 18 d are provided on the side surfaces of the feedercircuit substrate 10, so there is a spatial room on the back surface ofthe substrate 10. Thus, by arranging the coupling portions 21 a′ and 21b′, which are one end portions of the radiation plates 21 a and 21 b,substantially over the entire back surface, it is possible to improve adegree of coupling to which the feeder electrodes 19 a and 19 b arecoupled to the radiation plates 21 a and 21 b.

Twenty-Fourth Preferred Embodiment of Wireless IC Device, See FIG. 33

FIG. 33 shows a wireless IC device according to a twenty-fourthpreferred embodiment of the present invention. The twenty-fourthpreferred embodiment basically has a similar configuration to those ofthe first to nineteenth preferred embodiments, and differs from thefirst to nineteenth preferred embodiments in that a sealing resin 25 isapplied in between the radiation substrate 20 and the feeder circuitsubstrate 10. The sealing resin 25 is, for example, epoxy-based adhesiveand improves fixing strength and environmental resistance, and theadhesive has a dielectric constant higher than air. Thus, capacitancesbetween the feeder electrodes 19 a and 19 b and the radiation plates 21a and 21 b increase, and the degree of coupling increases. Note thatapplication of the sealing resin 25 is performed after the mountedelectrodes 24 a and 24 b and the mounting electrodes 18 a and 18 b areconnected by solder 41 (reflow solder), for example.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrodes 18a and 18 b are those described in the nineteenth preferred embodiment.

Twenty-Fifth Preferred Embodiment of Wireless IC Device, See FIG. 34

FIG. 34 shows a wireless IC device according to a twenty-fifth preferredembodiment of the present invention. The twenty-fifth preferredembodiment basically has a similar configuration to those of the firstto nineteenth preferred embodiments, and differs from the first tonineteenth preferred embodiments in that a resist film 29 that coversthe radiation plates 21 a and 21 b is provided on the radiationsubstrate 20. The resist film 29 is, for example, epoxy-based orpolyimide-based resin material and improves environmental resistance ofthe radiation plates 21 a and 21 b, and the resin material has adielectric constant higher than air. Thus, capacitances between thefeeder electrodes 19 a and 19 b and the radiation plates 21 a and 21 bincrease, and the degree of coupling increases. In addition, it ispossible to determine a gap between the radiation plates 21 a and 21 band the back surface of the feeder circuit substrate 20 based on thethickness of the resist film 29, it is possible to prevent variations indegree of coupling, and then the characteristic becomes stable.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrodes 18a and 18 b are those described in the nineteenth preferred embodiment.

Twenty-Sixth Preferred Embodiment and Twenty-Seventh PreferredEmbodiment of Wireless IC Device, See FIG. 35 and FIG. 36

FIG. 35 shows a wireless IC device according to a twenty-sixth preferredembodiment of the present invention. FIG. 36 shows a wireless IC deviceaccording to a twenty-seventh preferred embodiment of the presentinvention. The twenty-sixth preferred embodiment is formed so that theareas of the mounted electrodes 24 a and 24 b are increased from thosein the nineteenth preferred embodiment. The twenty-seventh preferredembodiment is constructed so that the areas of the mounted electrodes 24a to 24 d are increased from those in the twenty-second preferredembodiment.

The areas of the mounting electrodes 18 a to 18 d formed on the backsurface of the feeder circuit substrate 10 are equal to those of thenineteenth and twenty-second preferred embodiments, and the amount ofsolder for bonding is supplied in accordance with the areas of themounting electrodes 18 a to 18 d. Extra solder spreads over to themounted electrodes 24 a to 24 d, so it is possible to reduce thethickness of solder, and it is possible to prevent variations inthickness of solder. By so doing, variations in gaps between theradiation plates 21 a and 21 b and the feeder electrodes 19 a and 19 breduce, and the degree of coupling becomes stable. Then, it is desirablethat Au plating, or the like, is applied to the mounted electrodes 24 ato 24 d to apply coating such that solder wets to spread over themounting electrodes 24 a to 24 d.

In addition, as described in the twenty-fifth preferred embodiment, whenthe resist film 29 is formed on the radiation plates 21 a and 21 b, itis possible to determine a gap between the radiation plates 21 a and 21b and the back surface of the feeder circuit substrate 10 based on thethickness of the resist film 29. A similar advantage to this may beachieved by forming a protrusion on the back surface of the feedercircuit substrate 10 using a conductive layer or a resin layer.

Twenty-Eighth Preferred Embodiment of Wireless IC Device, See FIGS. 37Aand 37B

FIGS. 37A and 37B shows a wireless IC device according to atwenty-eighth preferred embodiment of the present invention. Thetwenty-eighth preferred embodiment basically has a similar configurationto those of the first to nineteenth preferred embodiments, and differsfrom the first to nineteenth preferred embodiments in that the couplingportions 21 a′ and 21 b′, which are one end portions of the radiationplates 21 a and 21 b, are integral with the mounted electrodes 24 a and24 b. Furthermore, the resist film 29 is arranged on the radiationplates 21 a and 21 b other than the mounted electrodes 24 a and 24 b.The mounted electrodes 24 a and 24 b are bonded to the mountingelectrodes 18 a and 18 b of the feeder circuit substrate 10 by solder41, or the like.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrodes 18a and 18 b are those described in the nineteenth preferred embodiment.Particularly, in the twenty-eighth preferred embodiment, because theradiation plates 21 a and 21 b include the mounted electrodes 24 a and24 b, the electrodes are easily formed, and the strength of the mountedelectrodes 24 a and 24 b increases.

Twenty-Ninth Preferred Embodiment of Wireless IC Device, See FIGS. 38Aand 38B

FIGS. 38A and 38B show a wireless IC device according to a twenty-ninthpreferred embodiment of the present invention. The twenty-ninthpreferred embodiment differs from the nineteenth preferred embodiment inthat the feeder electrodes 19 a and 19 b and the mounting electrodes 18a and 18 b are integrally formed. In this case, the feeder electrodes 19a and 19 b are different from those of the nineteenth preferredembodiment and are exposed on the back surface of the feeder circuitsubstrate 10. By so doing, it is possible to reduce distances betweenthe feeder electrodes 19 a and 19 b and the radiation plates 21 a and 21b (coupling portions 21 a′ and 21 b′) to increase capacitances. Inaddition, the size of the mounting electrodes 18 a and 18 b issubstantially increased, and it is possible to increase the strength ofthe mounting electrodes 18 a and 18 b.

Thirtieth Preferred Embodiment of Wireless IC Device, See FIG. 39

FIG. 39 shows a wireless IC device according to a thirtieth preferredembodiment of the present invention. The thirtieth preferred embodimentis constructed so that the radiation plates 21 a and 21 b are integratedwith the coupling portions 21 a′ and 21 b′, which are one end portions,and the coupling portions 21 a′ and 21 b′ are magnetically coupled tothe inductance elements L1 and L2 incorporated in the feeder circuitsubstrate 10. The feeder electrodes 19 a and 19 b preferably are part ofthe inductance elements L1 and L2. In addition, the mounted electrode 24is located at the center portion of the radiation substrate 20, and isconnected to the mounting electrode 18, provided on the back surface ofthe feeder circuit substrate 10, by solder 41, or the like.

The other configuration is similar to that of the first preferredembodiment. The basic operations and advantages as the wireless ICdevice are similar to those of the first preferred embodiment. Theoperations and advantages when provided with the mounting electrode 18are those described in the nineteenth preferred embodiment.Particularly, in the thirtieth preferred embodiment, the radiationplates 21 a and 21 b are magnetically coupled to the feeder circuitsubstrate 10, so the characteristic remains unchanged even when aposition at which the feeder circuit substrate 10 is mounted slightlydeviates or is deviated by rotating 180 degrees. In addition, a changein characteristic is small even when a resin material having a highdielectric constant is interposed between the feeder circuit substrate10 and the radiation plates 21 a and 21 b.

Thirty-First Preferred Embodiment, See FIG. 40 and FIG. 41

As shown in FIG. 40 and FIG. 41, the wireless IC device according to thethirty-first preferred embodiment of the present invention includes thewireless IC chip 5, a feeder circuit substrate 120, and a radiationplate 131. The wireless IC chip 5 processes transmission and receptionsignals of a predetermined frequency. The wireless IC chip 5 is mountedon the feeder circuit substrate 120 in an electrically connected state.The radiation plate 131 preferably includes an electrode film on thesurface of a printed circuit board 130. The integrated wireless IC chip5 and feeder circuit substrate 120 are referred to as an electromagneticcoupling module 100 below.

The feeder circuit substrate 120 includes a feeder circuit 121 having aresonant circuit/matching circuit that will be described below withreference to FIG. 45 and FIG. 47.

The wireless IC chip 5 preferably includes a clock circuit, a logiccircuit, a memory circuit, and the like. The wireless IC chip 5 storesnecessary information. As shown in FIG. 19, the pair of input/outputterminal electrodes 6 and the pair of mounting terminal electrodes 7 areprovided on the back surface of the wireless IC chip 5. In the feedercircuit substrate 120 shown in FIG. 46, the input/output terminalelectrodes 6 of the wireless IC chip 5 are electrically connected tofeeder terminal electrodes 142 a and 142 b through metal bumps, or thelike, and the mounting terminal electrodes are electrically connected tothe mounted electrodes 143 a and 143 b through metal bump, or the like.In addition, in the feeder circuit substrate 120 shown in FIG. 48, theinput/output terminal electrodes 6 are electrically connected to feederterminal electrodes 222 a and 222 b through metal bumps, or the like,and the mounting terminal electrodes 7 are electrically connected tomounted electrodes 223 a and 223 b through metal bumps, or the like.

A radiation plate 131 is preferably disposed on the surface of printedcircuit board 130 and includes an electrode film made of a nonmagneticmetal material. One end portion 131 a and the other end portion 131 beach are arranged to face the lower surface of the feeder circuitsubstrate 120, and are electromagnetically coupled to the feeder circuit121. The overall shape of the radiation plate 131 can be varied asdesired, and may be, for example, a loop shape or a dipole shape. Inaddition, the radiation plate 131 may be provided inside the printedcircuit board 130. Note that the printed circuit board 130 isincorporated in an article, such as a cellular phone.

Mounting electrodes 122 are preferably provided on two opposite sidesurfaces of the feeder circuit substrate 120 and are not electricallyconnected to the feeder circuit 121, which will be described in detailbelow. As shown in FIG. 41, the mounting electrodes 122 are disposed onthe side surfaces of a laminated body (feeder circuit substrate 120) inwhich an insulating material layer and an electrode layer are laminatedso as to expose the electrode layers, and are soldered to mounting lands132 provided separately from the radiation plate 131 on the printedcircuit board 130. The lands 132 are provided separately from theradiation plate 131. Both lands 132 preferably have substantially thesame thickness.

In the soldering, first, solder paste 133 is applied to the lands 132 asindicated by the broken line in FIG. 41 (thickness of application isabout 100 μm), and the electromagnetic coupling module 100 is placed ata predetermined position on the printed circuit board 130 by a mounter.The radiation plate 131 is provided on the surface of the printedcircuit board 130; however, the solder paste 133 is not applied to theradiation plate 131. After that, by passing through a reflow furnace,the mounting electrodes 122 and the lands 132 are soldered to eachother.

When the solder paste 133 is in a molten state in the reflow furnace,the solder paste 133 contacts each mounting electrode 122, and theelectromagnetic coupling module 100 is adhered onto the printed circuitboard 130. After being taken out from the reflow furnace, the solderpaste 133 contracts with a decrease in temperature, and hardens in abridge shape between the lands 132 and the mounting electrodes 122 togenerate internal stress in the arrow A direction. By so doing, thefeeder circuit substrate 120 is pulled toward the printed circuit board130, and the lower surface of the feeder circuit substrate 120 closelyadheres to the end portions 131 a and 131 b of the radiation plate 131.

When considering in detail the above phenomenon at the time ofsoldering, the above phenomenon is due to a situation that the mountingelectrodes 122 are provided on the side surfaces of the feeder circuitsubstrate 120 away from the lower surface (in other words, the mountingelectrodes 122 are disposed only on the side surfaces and not disposedon the lower surface), and a gap g is present between each land 132 andthe feeder circuit substrate 120. When the solder paste 133 at the gap gportion contracts at the time of hardening, stress in the arrow Adirection occurs.

The feeder circuit substrate 120 directly adheres to the radiation plate131 because of the stress due to contraction of the solder paste 133.Thus, the feeder circuit substrate 120 and the radiation plate 131 aredesirably coupled to each other without variations in gap therebetween,and variations in degree of coupling are substantially eliminated. Inaddition, because the mounting electrodes 122 are not electricallyconnected to the feeder circuit 121 and are independent, corrosion ofthe mounting electrodes 122 due to solder, or the like, does notadversely influence the electrical characteristic and reliability of theelectromagnetic coupling module 100.

In addition, the mounting electrodes 122 are disposed on the twoopposite side surfaces of the feeder circuit substrate 120, so it ispossible to mount the feeder circuit substrate 120 on the printedcircuit board 130 with a further improved accuracy in a well balancedmanner. Particularly, in the present preferred embodiment, because themounting electrodes 122 are provided on the two opposite side surfacesof the feeder circuit substrate 120 at line-symmetrical positions,mounting accuracy and balance are further improved.

Moreover, it is only necessary to use a simple manufacturing process,that is, soldering by a reflow furnace, no expensive mounter isrequired. In addition, after the soldering, the electromagnetic couplingmodule 100 preferably is coated with a resin material to further improvethe bonding strength of the electromagnetic coupling module 100 to theprinted circuit board 130.

Thirty-Second Preferred Embodiment, see FIG. 42 and FIG. 43

As shown in FIG. 42 and FIG. 43, the wireless IC device according to thethirty-second preferred embodiment basically has a similar configurationto that of the thirty-first preferred embodiment, so like referencenumerals denote like components or portions to those of the thirty-firstpreferred embodiment, and the description thereof is omitted.

The thirty-second preferred embodiment differs from the thirty-firstpreferred embodiment in that the mounting electrodes 122 are formed ofvia hole electrodes that are exposed on the side surfaces of thelaminated body (feeder circuit substrate 120). In order to expose thevia hole electrodes on the side surfaces of the laminated body, it isonly necessary that the via hole electrodes are arranged along a cutline of a mother substrate when the feeder circuit substrate 120 ismanufactured. A method of forming the above via hole electrodes(conductors) is described in Japanese Unexamined Patent ApplicationPublication No. 2002-26513 in detail.

In the thirty-second preferred embodiment, bonding the mountingelectrodes 122 and the lands 132 on the printed circuit board 130 by thesolder paste 133 is similar to that of the thirty-first preferredembodiment, and the operations and advantages thereof are also similar.

Alternative Preferred Embodiment, See FIG. 44

FIG. 44 shows the feeder circuit substrate 120 according to analternative preferred embodiment to the thirty-second preferredembodiment. The feeder circuit substrate 120 is constructed so thatrecesses 123 are formed on the side surfaces and the mounting electrodes122 are arranged in the recesses 123. By arranging the solder paste 133in the recesses 123, it is possible to prevent spreading of a solderfillet.

First Example of Feeder Circuit Substrate, See FIG. 45 and FIG. 46

Here, the first example of the feeder circuit substrate 120 will bedescribed. As shown in an equivalent circuit in FIG. 45, the feedercircuit substrate 120 includes the feeder circuit 121 that includes aresonant circuit/matching circuit having inductance elements L11 and L12that have different inductances and that are magnetically coupled(indicated by mutual inductance M) in opposite phases.

The inductance elements L11 and L12 included in the feeder circuit 121are magnetically coupled in opposite phases and resonate at a frequencyprocessed by the wireless IC chip 5, and are electromagnetically coupledto the end portions 131 a and 131 b of the radiation plate 131. Inaddition, the feeder circuit 121 is electrically connected to theinput/output terminal electrode 6 of the wireless IC chip 5 to match theimpedance (for example, about 50Ω) of the wireless IC chip 5 with theimpedance (spatial impedance of 377Ω, for example) of the radiationplate 131.

Thus, the feeder circuit 121 transmits a transmission signal having apredetermined frequency and output from the wireless IC chip 5 to theradiation plate 131, and selects a reception signal having apredetermined frequency from among signals received by the radiationplate 131 and then supplies the selected reception signal to thewireless IC chip 5. Thus, in the wireless IC device 1, the wireless ICchip 5 is activated by a signal received by the radiation plate 131, anda response signal from the wireless IC chip 5 is radiated outward fromthe radiation plate 131.

As described above, in the wireless IC device, the feeder circuit 121provided for the feeder circuit substrate 120 sets a resonant frequencyof a signal. Thus, even when the wireless IC device is attached tovarious types of articles, the wireless IC device operates without anychange. Hence, variations in radiation characteristic are prevented, andit is not necessary to change the design of the radiation plate 131, orthe like, for each individual article. Then, the frequency of thetransmission signal radiated from the radiation plate 131 and thefrequency of the reception signal supplied to the wireless IC chip 5substantially equal to the resonant frequency of the feeder circuit 121in the feeder circuit substrate 120. A maximum gain of a signal issubstantially determined by at least any one of the size or shape of thefeeder circuit 121, a distance or a medium between the feeder circuit121 and the radiation plate 131. The frequencies of the transmission andreception signals are determined on the feeder circuit substrate 120.Thus, irrespective of the shape, size, arrangement, or the like, of theradiation plate 131, for example, even when the wireless IC device isrolled or held between dielectric materials, the frequencycharacteristic remains unchanged, and the stable frequencycharacteristic may be obtained.

Next, the configuration of the feeder circuit substrate 120 will bedescribed with reference to FIG. 46. The feeder circuit substrate 120 isconstructed so that laminated ceramic sheets 141 a to 141 i made of adielectric material (dielectric material or magnetic material) arepressure-bonded and fired. Feeder terminal electrodes 142 a and 142 b,mounted electrodes 143 a and 143 b and via hole conductors 144 a, 144 b,145 a and 145 b are provided on the uppermost layer sheet 141 a. On eachof the second to eighth layer sheets 141 b to 141 h, wiring electrodes146 a and 146 b that constitute the inductance elements L11 and L12 areprovided, and via hole conductors 147 a, 147 b, 148 a and 148 b, or thelike, are formed where necessary. Planar electrodes 149 a and 149 b areprovided on the lowermost layer sheet 141 i. The planar electrodes 149 aand 149 b have an outer shape equal to or smaller than those of theinductance elements L11 and L12 when the feeder circuit substrate 120 isviewed in plan.

By laminating the above sheets 141 a to 141 i, the inductance elementL11 in which the wiring electrodes 146 a are spirally connected throughthe via hole conductors 147 a, and the inductance element L12 in whichthe wiring electrodes 146 b are spirally connected through the via holeconductors 147 b, are formed. In addition, capacitances are formedbetween the lines of each of the wiring electrodes 146 a and 146 b.

An end portion 146 a-1 of the wiring electrode 146 a on the sheet 141 bis connected to the feeder terminal electrode 142 a through a via holeconductor 145 a. An end portion 146 a-2 of the wiring electrode 146 a onthe sheet 141 h is connected to the feeder terminal electrode 142 bthrough via hole conductors 148 a and 145 b. An end portion 146 b-1 ofthe wiring electrode 146 b on the sheet 141 b is connected to the feederterminal electrode 142 b through a via hole conductor 144 b. An endportion 146 b-2 of the wiring electrode 146 b on the sheet 141 h isconnected to the feeder terminal electrode 142 a through via holeconductors 148 b and 144 a. Furthermore, end portions 146 a-2 and 146b-2 of the wiring electrodes 146 a and 146 b are connected to the planarelectrodes 149 a and 149 b through via hole conductors.

In the above described feeder circuit 121, the inductance elements L11and L12 are respectively wound in opposite directions, so magneticfields generated in the inductance elements L11 and L12 are cancelled.Because the magnetic fields are cancelled, it is necessary to extend thewiring electrodes 146 a and 146 b in order to obtain desiredinductances. By so doing, because the Q value decreases, the steepresonant characteristic disappears, and a wide band is obtained aroundthe resonant frequency.

The inductance elements L11 and L12 are located at left and rightdifferent positions when the feeder circuit substrate 120 is viewed inplan. In addition, magnetic fields generated in the inductance elementsL11 and L12 are opposite in directions. By so doing, when the feedercircuit 121 is coupled to the end portions 131 a and 131 b of the loopradiation plate 131, electric currents in opposite directions areexcited in the end portions 131 a and 131 b. Thus, it is possible totransmit and receive signals by the loop radiation plate 131. Note thatthe inductance elements L11 and L12 may be respectively coupled to twodifferent radiation plates.

When the feeder circuit substrate 120 is made of a magnetic material,and the inductance elements L11 and L12 are provided in the magneticmaterial, it is possible to obtain large inductances, and it is possibleto handle a frequency of approximately 13.56 MHz band, for example. Inaddition, even when variations in machining of the magnetic sheets orvariations in permeability occur, it is possible to absorb variations inimpedance with the wireless IC chip 5. The permeability μ of themagnetic material is desirably about 70.

In addition, because the two inductance elements L11 and L12 havedifferent inductances, the feeder circuit 121 has a plurality ofresonant frequencies to make it possible to widen the band of thewireless IC device. However, the inductances of the inductance elementsL11 and L12 may be set at substantially the same value. In this case, itis possible to equalize the magnitudes of the magnetic fields generatedin the inductance elements L11 and L12. By so doing, it is possible toequalize the amount by which the magnetic fields are cancelled in thetwo inductance elements L11 and L12, and a wide band is obtained aroundthe resonant frequency.

Note that the feeder circuit substrate 120 include a multilayersubstrate made of ceramics or resin or may be a substrate includinglaminated flexible sheets made of a dielectric material, such aspolyimide and liquid crystal polymer. Particularly, the inductanceelements L11 and L12 are incorporated in the feeder circuit substrate120. Thus, the feeder circuit 121 is less likely to experienceinterference or influence from outside the substrate, and it is possibleto prevent variations in radiation characteristic.

In addition, by providing the planar electrodes 149 a and 149 b betweenthe inductance elements L11 and L12 and the radiation plate 131, it ispossible to prevent variations in coupling between the feeder circuit121 and the radiation plate 131. Note that the planar electrodes 149 aand 149 b need not be electrically connected to the wiring electrodes146 a and 146 b, and the planar electrodes 149 a and 149 b are notnecessary.

Second Example of Feeder Circuit Substrate, See FIG. 47 and FIG. 48

The second example of the feeder circuit substrate 120 includes anequivalent circuit shown in FIG. 47 and a laminated structure shown inFIG. 48. The feeder circuit substrate 120 is constructed so thatlaminated ceramic sheets 221 a to 221 h made of a dielectric material(dielectric material or magnetic material) are pressure-bonded andfired. Feeder terminal electrodes 222 a and 222 b and mounted electrodes223 a and 223 b are provided on the uppermost layer sheet 221 a. Awiring electrode 225 is provided on the second layer sheet 221 b. Wiringelectrodes 225 a and 225 b that constitute the inductance elements L11and L12 are provided on the third to seventh layer sheets 221 c to 221g. Planar electrodes 228 a and 228 b are provided on the lowermost layersheet 221 h. Note that description of via hole conductors formed in thesheets 221 a to 221 f is omitted for the sake of simplification.

By laminating the sheets 221 a to 221 h, the inductance element L11 inwhich the wiring electrodes 225 a are spirally connected through the viahole conductors, and the inductance element L12 in which the wiringelectrodes 225 b are spirally connected through the via hole conductors,are formed. In addition, capacitances are formed between the lines ofeach of the wiring electrodes 225 a and 225 b.

The wiring electrodes 225 a and 225 b are integrated in a wiringelectrode 225 on the sheet 221 b. An end portion 225 a′ of the wiringelectrode 225 a on the sheet 221 g is connected to a feeder terminalelectrode 222 a through a via hole conductor. An end portion 225 b′ ofthe wiring electrode 225 b is connected to a feeder terminal electrode222 b through a via hole conductor.

The feeder circuit 121 that includes the thus configured inductanceelements L11 and L12 is the equivalent circuit shown in FIG. 47. Theinductance elements L11 and L12 connected in series with the wireless ICchip 5 are magnetically coupled to each other in opposite phases andresonate at a frequency processed by the wireless IC chip 5, and areelectromagnetically coupled to the radiation plate 131. In addition, thefeeder circuit 121 matches the impedance (for example, about 50Ω) of thewireless IC chip 5 with the impedance (spatial impedance of about 377Ω,for example) of the radiation plate 131.

Thus, the operations and advantages of the second example are similar tothose of the above first example. Particularly, by providing the planarelectrodes 228 a and 228 b on the back surface of the feeder circuitsubstrate 120, it is possible to prevent variations in coupling betweenthe feeder circuit 121 and the radiation plate 131. Note that the planarelectrodes 228 a and 228 b are not necessary.

Summary of Preferred Embodiments

In a wireless IC device, it is desirable to provide a mounting electrodeon a surface of a feeder circuit substrate. When the mounting electrodeis provided separately from a feeder electrode and bonded onto asubstrate of a radiation plate (for example, electrical connection by aconductive material, such as solder, or connection by an insulatingmaterial), the bonding strength improves. Thus, even when the wirelessIC device receives an impact due to a drop, or the like, or when thermalstress is applied to the radiation substrate or the feeder circuitsubstrate, it does not adversely influence electromagnetic couplingbetween the feeder electrode and the radiation plate. Particularly, itis desirable to form the mounting electrode at an outer edge portion ofthe feeder circuit substrate. This makes it possible to improve theaccuracy of a position at which the feeder circuit substrate is mounted.In addition, the mounting electrode may be disposed on a side surface ofthe feeder circuit substrate. When the mounting electrode is disposed onthe side surface, there will be a spatial room on the back surface ofthe feeder circuit substrate. Thus, it is possible to utilize almost allthe back surface for coupling with the radiation plate. This increases adegree of coupling between the feeder electrode and the radiation plate.

Particularly, by soldering the mounting electrode, which is provided onthe side surface of the feeder circuit substrate, onto a mounting landon the substrate on which the radiation plate is provided, a lowersurface of the feeder circuit substrate closely adheres to the radiationplate because of hardening contraction of solder. Thus, the feedercircuit substrate and the radiation plate are desirably coupled to eachother without variations in gap therebetween, and variations in degreeof coupling are substantially eliminated.

The mounting electrode is preferably disposed on each of two oppositeside surfaces of the feeder circuit substrate. It is possible to mountthe feeder circuit substrate on the substrate with a further improvedaccuracy in a well balanced manner. Because the mounting electrode isprovided on each of the two opposite side surfaces of the feeder circuitsubstrate at a line-symmetrical position, mounting accuracy and balanceare further greatly improved.

The mounting electrode may be located at a distance spaced away from thelower surface of the feeder circuit substrate. This prevents solder fromspreading to the lower surface of the feeder circuit substrate. Thus, itis possible to ensure close contact between the feeder circuit substrateand the radiation plate.

The feeder circuit substrate preferably includes a laminated body inwhich an insulating material layer and an electrode layer are laminated,and the mounting electrode may be arranged so as to expose an electrodelayer on at least one of the side surfaces of the laminated body. Byforming the mounting electrode using the electrode layer that ispartially exposed on the side surface of the laminated body, themounting strength of the feeder circuit substrate improves.

In addition, the feeder circuit substrate preferably includes alaminated body in which an insulating material layer and an electrodelayer are laminated, and the mounting electrode may be arranged in arecess that is formed on at least one of the side surfaces of thelaminated body. By arranging solder in the recess, it is possible toprevent spreading of a solder fillet.

In addition, a resonant circuit and/or a matching circuit may beprovided in the feeder circuit substrate. In addition, the radiationplate may be disposed on a surface and/or inside of the radiationsubstrate. In addition, the feeder electrode may be arranged over arange from a surface, facing the radiation plate, of the feeder circuitsubstrate to at least one of surfaces, not facing the radiation plate,of the feeder circuit substrate. The bonding strength of the feederelectrode improves. A plurality of the feeder electrodes or the mountingelectrodes may be provided.

An inductance element and a capacitance element may be respectivelyprovided on the feeder circuit substrate at different positions in planview and are electromagnetically coupled to different feeder electrodes,and different radiation plates may be respectively coupled to the feederelectrodes. Because capacitive coupling is higher in efficiency ofexchanging signal energy than magnetic coupling, it is possible toimprove the radiation characteristic. In addition, a coupled state tothe feeder electrode may be set separately between the inductanceelement and the capacitance element, so the degree of freedom fordesigning the radiation characteristic improves.

In addition, the resonant circuit or the matching circuit may beconfigured so that the wireless IC is galvanically connected to thefeeder electrode. In addition, the resonant circuit or the matchingcircuit may include an element incorporated in the feeder circuitsubstrate and an element mounted on the feeder circuit substrate or anelement mounted on a substrate on which the radiation plate is provided.When a chip inductor having a large inductance or a chip capacitorhaving a large capacitance is mounted on the feeder circuit substrate orthe radiation substrate, the element incorporated in the feeder circuitsubstrate may have a small inductance or capacitance. Thus, it ispossible to further reduce the size of the feeder circuit substrate.

The feeder circuit desirably includes at least two inductance elementshaving different inductances. Because of the different inductances, thefeeder circuit may have a plurality of resonant frequencies to widen theband of the wireless IC device. Thus, it is possible to use the wirelessIC device in all the countries of the world without any change indesign.

It is desirable that the feeder circuit is electromagnetically coupledto the radiation plate, and the resonant frequency of a signal radiatedfrom the radiation plate is substantially equal to the self-resonantfrequency of the feeder circuit. Because the frequency of a signal isdetermined by the feeder circuit, so the length or shape of theradiation plate is selectable, and the degree of freedom for designingthe radiation plate improves. In addition, irrespective of the shape,size, arrangement, or the like, of the radiation plate, for example,even when the wireless IC device is rolled or held between dielectricmaterials, the frequency characteristic remains unchanged, and thestable frequency characteristic may be obtained. In addition, even whenthe wireless IC device is attached to various types of articles, thewireless IC device operates without any change. Hence, variations inradiation characteristic are prevented, and it is not necessary tochange the design of the radiation plate, or the like, for eachindividual article.

It is desirable that no electrode is provided on the lower surface ofthe feeder circuit substrate. This prevents solder from spreading to thelower surface of the feeder circuit substrate. Thus, it is possible toreliably ensure close contact between the feeder circuit substrate andthe radiation plate.

The feeder circuit substrate may include a multilayer substrate made ofceramics or liquid crystal polymer. When the feeder circuit substrate isdefined by a multilayer substrate, it is possible to highly accuratelyincorporate the inductance element or the capacitance element, and adegree of freedom for forming wiring electrodes is greatly improved.

In addition, it is desirable that a sealing resin is provided betweenthe radiation substrate and the feeder circuit substrate or a protectionfilm that covers at least one of the wireless IC chip, the feedercircuit substrate and the radiation plate is provided. The environmentalresistance is greatly improved.

In addition, it is desirable that the imaginary portion of aninput/output impedance of the wireless IC conjugates with the imaginaryportion of an impedance when viewed from a portion of the feeder circuitsubstrate, connected to the wireless IC, toward the feeder electrodewithin or near a range of frequency used.

Alternative Preferred Embodiments

Note that the wireless IC device and the electronic apparatus accordingto the present invention are not limited to the above preferredembodiments; they may be modified into various forms within the scope ofthe present invention.

For example, the resonant circuit may have various configurations,elements and arrangements. In addition, the materials of the variouselectrodes and feeder circuit substrate described in the preferredembodiments are only illustrative, and a selected material may be usedas long as the material has a necessary property. In addition, to mountthe wireless IC chip on the feeder circuit substrate, a process otherthan the metal bump may be used. It is applicable that the wireless ICis not of a chip type but the wireless IC is disposed on the feedercircuit substrate. Furthermore, to fix the mounting electrode of thefeeder circuit substrate to the mounting land, adhesive that hardens tocontract may be used instead of solder, for example.

In addition, the electronic apparatus equipped with the wireless ICdevice according to the present invention is not limited to a cellularphone but it may be various wireless communication devices or householdelectrical appliances, such as a television and a refrigerator.

As described above, the present invention is useful for a wireless ICdevice and an electronic apparatus, and is particularly advantageous inthat it is possible to achieve miniaturization, allows simple andlow-cost mounting of a wireless IC, and eliminates the possibility ofany damage from occurring to the wireless IC due to static electricity.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing the scope andspirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

1. A wireless IC device comprising: a wireless IC arranged to transmitand receive signals; a feeder circuit substrate including a feedercircuit incorporating an inductance element connected to the wireless ICin a galvanically conductive state and in which a feeder electrodecoupled to the inductance element is provided on a surface of the feedercircuit substrate or an inside of the feeder circuit substrate; aradiation plate that is electromagnetically coupled to the feederelectrode; and a mounting electrode provided on a surface of the feedercircuit substrate; wherein the mounting electrode is electricallyindependent from the feeder circuit.
 2. The wireless IC device accordingto claim 1, wherein, between the feeder electrode and the mountingelectrode, the mounting electrode is disposed at an outer edge portionof the feeder circuit substrate.
 3. The wireless IC device according toclaim 1, wherein the mounting electrode is disposed on a side surface ofthe feeder circuit substrate.
 4. The wireless IC device according toclaim 3, wherein the mounting electrode is disposed on each of twoopposite side surfaces of the feeder circuit substrate.
 5. The wirelessIC device according to claim 3, wherein the mounting electrode isdisposed on each of the two opposite side surfaces of the feeder circuitsubstrate at line-symmetrical positions.
 6. The wireless IC deviceaccording to claim 3, wherein the mounting electrode is disposed at adistance spaced away from a lower surface of the feeder circuitsubstrate.
 7. The wireless IC device according to claim 3, wherein thefeeder circuit substrate includes a laminated body in which aninsulating material layer and an electrode layer are laminated, and themounting electrode is arranged so as to expose the electrode layer on atleast one of surfaces of the laminated body.
 8. The wireless IC deviceaccording to claim 3, wherein the feeder circuit substrate includes alaminated body in which an insulating material layer and an electrodelayer are laminated, and the mounting electrode is arranged in a recessformed on at least one of side surfaces of the laminated body.
 9. Thewireless IC device according to claim 1, further comprising a resonantcircuit that is provided in the feeder circuit substrate.
 10. Thewireless IC device according to claim 9, wherein the resonant circuit orthe matching circuit is arranged so that the wireless IC is galvanicallyconnected to the feeder electrode.
 11. The wireless IC device accordingto claim 9, wherein the resonant circuit or the matching circuitincludes an element incorporated in the feeder circuit substrate and anelement mounted on the feeder circuit substrate.
 12. The wireless ICdevice according to claim 9, wherein the resonant circuit or thematching circuit includes an element provided for the feeder circuitsubstrate and an element mounted on a substrate for which the radiationplate is provided.
 13. The wireless IC device according to claim 1,further comprising a matching circuit that is provided in the feedercircuit substrate.
 14. The wireless IC device according to claim 1,wherein the radiation plate is provided on at least one of a surface oran inside of a radiation substrate.
 15. The wireless IC device accordingto claim 1, further comprising a substrate-side mounted electrode thatis provided on a surface of a radiation substrate in which the radiationplate is provided, wherein the substrate-side mounted electrode iselectrically connected to the mounting electrode of the feeder circuitsubstrate.
 16. The wireless IC device according to claim 15, wherein thesubstrate-side mounted electrode is electrically connected to theradiation plate.
 17. The wireless IC device according to claim 1,wherein the feeder electrode is arranged over a range from a surface,facing the radiation plate, of the feeder circuit substrate to at leastone of surface of the feeder circuit substrate that does not face theradiation plate.
 18. The wireless IC device according to claim 1,wherein a plurality of the radiation plates are provided.
 19. Thewireless IC device according to claim 1, wherein at least one of aplurality of the feeder electrodes or a plurality of the mountingelectrodes are provided on a surface of the feeder circuit substrate.20. The wireless IC device according to claim 1, further comprising asealing resin that is provided between a radiation substrate, on whichthe radiation plate is provided, and the feeder circuit substrate. 21.The wireless IC device according to claim 1, wherein the feeder circuitincludes at least two inductance elements having different inductances.22. The wireless IC device according to claim 1, wherein the feedercircuit substrate includes the inductance element and a capacitanceelement at different positions in plan view, the capacitance element iselectromagnetically coupled to a feeder electrode that is different fromthe feeder electrode to which the inductance element iselectromagnetically coupled, and the different radiation plates arerespectively coupled to the feeder electrodes in a galvanicallynon-conductive state.
 23. The wireless IC device according to claim 1,wherein the feeder circuit substrate is defined by a multilayersubstrate.
 24. The wireless IC device according to claim 1, furthercomprising a protection film arranged to cover at least one of awireless IC chip arranged to transmit and receive signals, the feedercircuit substrate and the radiation plate.
 25. The wireless IC deviceaccording to claim 1, wherein an imaginary portion of an input/outputimpedance of the wireless IC device conjugates with the imaginaryportion of an impedance when viewed from a portion of the feeder circuitsubstrate, connected to the wireless IC, toward the feeder electrodewithin or near a range of frequency used.
 26. An electronic apparatuscomprising the wireless IC device according to claim
 1. 27. Anelectronic apparatus comprising the wireless IC device according toclaim 1, wherein the radiation plate is provided for a printed wiringboard incorporated in an apparatus casing, and the feeder electrodeprovided for the feeder circuit substrate is electromagnetically coupledto the radiation plate.